51Cr diffusion in α-Zr single crystals

The volume diffusion coefficients of the fast-diffusing solute 51Cr have been obtained in oriented α-Zr single crystals, in the directions parallel and perpendicular to the c axis. The dependence of these diffusion coefficients on temperature was also measured between 7500C and 8480C. Single crystals were grown by thermal cycling through the α -><- β transformation temperature (8620C). Diffusion coefficients were measured using the 'thin film' method. In some experiments non-Gaussian penetration profiles were obtained and this behaviour is also analyzed. The diffusion of 51Cr is faster in the c axis direction, with Qsub(parallel)(153 kJ/mol) < Qsub(perpendicular to) (163 kJ/mol). The anisotropy factor fsub(a) = Dsub(parallel)/Dsub(perpendicular to) approx.= 3. This factor, the activation energies and frequency factors are discussed in comparison with those of other solutes. (orig.)